Can Painful Foot Surgery Stitches Cause An Infection?

My husband had an operation on his foot 6 weeks ago he had stiches out 10 days post op but went back to gp because his foot was hot and swollen he had an infection & was given antibiotics. He then found 3 stiches that the gp did not remove and it was causing him consideral pain he did return last week to gp after finding the first 3 stiches the GP checked the wound and assured him all stiches were removed but gave him another week supply of antibiotics two different ones saying his infection was not totally cleared, but tonight after he has been complaing for the past week of pain in his foot,I have taken out two more stiches that were quite deep as new skin had started to form over the scar. Could he still have the infection? he is now put off going to gp as he has lost confidence in them I am concerned that the infection may get worse and can't be sure all the stiches are removed. What sould he do?